$$x^2y^4-b^2x^4$$

$$2\frac{d^2y}{dx^2}-4\frac{dy}{dx}+2y=2x$$

$$15\left(\log a-\log b\right)$$

$$sin\left(30-x\right)$$

$$\int b^2e^{-12b}db$$

$$\left(6a^2+\frac{12}{2}\right)+\left(5a^2+\frac{10}{2}\right)$$

$$-2x-6$$